This invention relates to an improved fiber optic diffuser for use in photodynamic therapy (hereinafter PDT). More particularly, the invention is directed to the construction of a fiber optic tip which improves the distribution of light dispersed and propagated from the optical fiber tip to achieve an approximately uniform cylindrical light pattern.
In recent years, PDT has become a common technique in the treatment of cancer through utilization of light-causing chemical reactions. For example, McCaughan, Jr. U.S. Pat. No. 4,660,925 provides a disclosure of many techniques and problems associated with PDT, not the least of which is apparatus that must carry intense radiation without overheating or self-destruction. It has been determined that the apparatus used for PDT laser light transmission along a fiber optic must be able to transmit such intense radiation without developing "hot spots" (optical, thermal or mechanical) and must be able to perform such optical radiating tasks under adverse environmental conditions. It has been known to use a variety of chemical etching techniques and roughening procedures to effect the desired diffusion of light into the desired radiation pattern. In fact, U.S. Pat. No. 4,660,925 makes reference to a Quentron fiber having a tapered point.